Anti-inflammatory properties of an oxidized sterol

A polar photoproduct of cholesterol oxidation, 7-ketocholesterol, was able to inhibit in a dose-dependent manner the mouse ear-swelling response to irritants such as croton oil or cantharidin. Its anti-inflammatory properties were much less than equivalent concentrations of hydrocortisone, but the oxidized sterol did not induce any systemic effects (as measured by thymolytic activity), as did topical hydrocortisone. It is concluded that 7-ketocholesterol has weak anti-inflammatory activity, and its mode of action may be different from that of glucocorticoids.     

Topical anti-inflammatory activity of human recombinant epidermal growth factor.

The topical anti-inflammatory activity of epidermal growth factor (EGF) was evaluated in inflammation models induced by 12-Otetradecanoylphorbol-13-acetate, croton oil and arachidonic acid. When EGF (1.5, 3 or 6 microg/ear) was coapplied with each inflammatory agent, there was a dose-related decrease in inflammation as assessed by ear punch weights, myeloperoxidase activity as well as by histopathological studies. The precise anti-inflammatory action of EGF is yet unclear, but we believe that interference with arachidonic acid metabolism may play an important role.     

Topical betamethasone 17-valerate is an anticorticosteroid in the rat

In the oxazolone-induced delayed hypersensitivity inflammation in the rat ear, betamethasone 17-valerate, in contrast to other topical corticosteroids, is incapable of suppressing oedema. When given in combination with triamcinolone acetonide, betamethasone 17-valerate competitively anta-gonizes the anti-inflammatory action of the active steroid. When tested in the mouse, betamethasone 17-valerate behaved as an anti-inflammatory agent 15 and 80 times as potent as betamethasone and hydrocortisone respectively. In an in vitro lymphocyte culture system in which preincubation with corticosteroids prevents subsequent phytohaemagglutinin induced DNA synthesis, betamethasone 17-valerate was less active than even hydrocortisone when rat lymph node cells were used, but with human cell preparations it was more potent than either hydrocortisone or betamethasone. Betamethasone 17-valerate behaves uniquely in the rat as an anticorticosteroid; in mouse and in man the compound behaves as a normal corticosteroid.     

一种增生性瘢痕动物模型的建立

目的建立一种兔耳瘢痕动物模型,观察兔耳腹侧创面在伤后不同时间瘢痕增生的情况。方法于38只新西兰兔的72只兔耳腹面手术切除2 cm×5 cm全层皮肤,创面用1%磺胺嘧啶银冷霜外敷包扎至愈合,换药隔日1次。未做手术的4只兔耳作对照。术后连续8个月观察兔耳创面自然愈合情况;用光镜观察兔耳创面瘢痕增生情况;分别用计算机图像分析系统和游标卡尺测量瘢痕胶原含量和瘢痕指数变化情况。结果兔耳创面上皮化后其色泽、厚度和质地均经历从瘢痕形成、成熟到退化的演变过程;1个月的瘢痕指数0.41±0.14,胶原含量30.69±12.39,分别较3-8个月为低(P<0.05),其变化与人体增生性瘢痕增生程度的消长趋势吻合。结论兔耳腹面全层皮肤缺损诱导的增生性瘢痕动物模型与人体增生性瘢痕相似,该模型可作为研究增生性瘢痕的发生机制及评估其治疗方法的较好的动物模型。     

Alkane-induced edema formation and cutaneous barrier dysfunction

Summary Certain mineral oils and hydrocarbons require repeated topical application to cause irritation. A structure activity relationship of pure n-alkanes was undertaken in a mouse ear edema model to investigate the mechanism of cumulative irritancy. Alkanes were applied twice daily over a 4-day period. Dodecane was found to be non-irritating, while tridecane elicited a response only at 96 h. Tetradecane was the strongest irritant with significant increases (p<0.05) in ear thickness observed at 48 h. Hexadecane, octadecane, and eicosane exhibited progressively decreasing activity. Permeability of the ears to hydrocortisone was monitored in vitro during tridecane-and tetradecane-induced irritation. Significant increases in permeability were observed 24 h before edema formation. A positive correlation was found between the extent of edema formation and enhancement of permeability. Loss of barrier function would result in increased cutaneous availability of the alkanes. Increased permeability prior to edema formation indicates that induction of barrier dysfunction may be a factor in the mechanism of alkane-induced irritation.     

Sterile cutaneous pustules: a manifestation of primary irritancy? Identification of contact pustulogens

An animal model (the rabbit) was used to define which of 8 chemicals caused pustule formation on topical application. Large occlusive chambers (diameter 12 mm), petrolatum as the vehicle and wrapping contributed to efficient occlusion and pustulation. Sodium lauryl sulfate and mecuric chloride gave reproducible results and clear dose-responses indicating that this pustulation is an expression of primary irritancy. Ammonium fluoride pustulation was not reproducible; croton oil pustules were more difficult to evaluate due to simultaneous erythema and edema. Sodium arsentate, nickel sulfate and potassium iodide pustules developed at sites where the skin barriers had been damaged by a stab injury. Benzalkonium chloride caused yellow staining and edema but not pustules. Because of lack of epidemiologic data, we do not know how frequently similar findings occur in man.     

Objective assessment of topical corticosteroids and non-steroidal anti-inflammatory drugs in methyl-nicotinate-induced skin inflammation

The aim of this study was to compare the activities of the two main classes of topical anti-inflammatory drugs in methyl-nicotinate-induced skin inflammation, using a new methodology based on laser-Doppler velocimetry. Six topical non-steroidal anti-inflammatory drugs (NSAIDs) (bufexamac, diclofenac, ibuprofen, indomethacin, phenylbutazone and niflumic acid) and three topical corticosteroids (clobetasol propionate, hydrocortisone and hydrocortisone butyrate) were tested. Drugs were commercially available (except indomethacin) and were applied under occlusion for 4 h to the forearms of 16 healthy male volunteers. Thirty minutes after excess drug removal, skin inflammation was induced by a 1-min application of methyl nicotinate (3 mM). This was repeated 44 h later. Each methyl-nicotinate application was followed by continuous skin blood flow recordings over 1 h. Overall, NSAIDs proved more effective than corticosteroids in inhibiting methyl-nicotinate-induced increases in skin blood flow. Diclofenac and indomethacin showed a potent prolonged inhibitory effect. Different types of activity were observed in the corticosteroid group: (a) At 30 min, hydrocortisone and hydrocortisone butyrate moderately inhibited methyl-nicotinate reactions whereas clobetasol propionate produced no detectable effects; (b) at 44 h, clobetasol propionate produced a significant inhibition whereas hydrocortisone butyrate and hydrocortisone exhibited either weak or no inhibitory action at all. These pharmacodynamic discrepancies between the corticosteroids tested could be related to differences in drug affinity to cutaneous receptors and in vasoconstrictive potency.     

Assessment of skin irritancy: measurement of skin fold thickness

It is desirable to use more objective methods than visual scoring for the assessment of skin irritancy reactions. The edema, or fluid accumulation in the exposed skin sites, can be accurately measured by a caliper and this alternative method of assessment is evaluated from different aspects. Sodium lauryl sulfate (SLS) and non-anoic acid in different concentrations were applied daily to human and animal (rabbit and guinea pig) skin, and a dose-response relationship established. Higher concentrations of the irritants induced an earlier response. With 5% SLS as the test substance and the increase in skin fold thickness as the single parameter of skin irritancy, the guinea pig was found to be less reactive than rabbit and man. Measurement techniques, reproduceability and advantages and disadvantages with different animal models are discussed.     

脂氧素A_4抑制实验性皮肤炎症与增殖反应的机制

目的探讨脂氧素A4(LXA4)对皮肤炎症与增殖反应的作用及其机制。方法应用欧亚瑞香脂制备小鼠的外耳炎症与增殖反应模型,应用LXA4(1nmol/L,10nmol/L)局部注射,4h1次,对部分小鼠静脉注射伊文思蓝或[3H]胸腺嘧啶。24h后测定外耳湿重(反映水肿)、伊文思蓝比色(反映血管通透性)、弹性硬蛋白酶活性(反映中性粒细胞浸润)、白介素8(IL8)蛋白与基因表达、核因子κB(NFκB)活化;72h后测定[3H]胸腺嘧啶掺入量。结果在欧亚瑞香脂模型耳,24h后外耳湿重、伊文思蓝比色、弹性硬蛋白酶活性、IL8蛋白与基因表达、NFκB活化均升高。LXA4治疗24h后抑制这些参数的升高;72h后,外耳组织的[3H]胸腺嘧啶掺入量升高,LXA4治疗后可抑制其升高。结论LXA4可抑制欧亚瑞香脂所致的外耳炎症与增殖反应,其机制与抑制浸润中性粒细胞的NFκB活化与IL8合成有关。     

Assessment of the antiphlogistic effect of naftifin-HCl in the UV-B erythema test

In a placebo-controlled double-blind comparative study conducted in 19 healthy volunteers, naftifin hydrochlorid cream was tested against clotrimazole 1%, clotrimazole 1%+hydrocortisone 1%, and various hydrocortisone preparations (0.5%; 1%; 2.5%) for erythema-suppressive effects. The anti-inflammatory effect of naftifine hydrochloride demonstrated earlier was confirmed in this study. The results prove a potency comparable to that of weak topical glucocorticosteroids.     

Novel anti-inflammatory properties of the angiogenesis inhibitor vasostatin

Endothelial cells are critically involved in the pathogenesis of inflammation, which is characterized by vasopermeability, plasma leakage, leukocyte recruitment, and neovascularization. Therefore, inhibitors of endothelial cell function could reduce inflammation. In this study, we evaluated the effects of the angiogenesis inhibitor vasostatin on inflammations induced by contact hypersensitivity reactions in mouse ears. Vasostatin-treated mice revealed significantly reduced edema formation, resulting from lower plasma leakage and inhibition of inflammation-associated vascular remodeling. Intravital microscopy studies of inflamed ears showed a decrease in the fraction of rolling leukocytes in vasostatin-treated mice, and Lycopersicon esculentum lectin-perfused ears revealed fewer leukocytes adherent to the vessel wall. The inflammatory infiltrate from vasostatin-treated mice was characterized by fewer CD8+ T cells, neutrophils, and macrophages compared to the saline-treated animals. In a modified Miles assay, vasostatin inhibited vascular endothelial growth factor-A-induced permeability, and inflamed ear tissues from vasostatin-treated mice expressed significantly reduced levels of the vascular destabilizer angiopoietin-2. These results reveal a previously unrecognized anti-inflammatory property of the angiogenesis inhibitor vasostatin, and suggest that vasostatin is a potential candidate drug for the treatment of inflammation.     

Strain-dependent effects of the histamine H₄ receptor antagonist JNJ7777120 in a murine model of acute skin inflammation

The effects of the histamine H(4) receptor antagonist JNJ7777120 were evaluated in a model of acute skin inflammation induced by local application of croton oil. The influence of strain on the effect of JNJ7777120 was investigated in four different mouse strains (CD-1, NMRI, BALB/c and C57BL/6J). In CD-1 mice, JNJ777720 (30-100 mg/kg subcutaneously, s.c.) exerted a dose-dependent inhibition of croton oil-induced ear inflammation and polymorphonuclear leucocyte infiltration, as confirmed by histological evaluation of ear tissues. JNJ7777120 (30-100 mg/kg) did not reduce ear oedema in NMRI, BALB/c or C57BL/6J mice. The positive control, dexamethasone (2 mg/kg s.c.) induced significant anti-inflammatory effects only in CD-1 and NMRI mice. In these strains, also the histamine H(1) -receptor blocker pyrilamine (30 mg/kg s.c.) significantly reduced ear oedema at 2 h after croton oil challenge, being as effective as JNJ7777120 in CD-1 mice. Taken together, these data demonstrate that the H(4) receptor antagonist JNJ7777120 may reduce acute croton oil-induced skin inflammation as effectively as H(1) receptor blockade. However, present experiments evidenced for the first time marked strain-related differences in the JNJ7777120 pharmacological activity, which have to be carefully considered when using this ligand to characterize histamine H(4) receptor functions in murine models and translating preclinical data to clinical human settings.     

成纤维细胞生长因子10单克隆抗体对豚鼠银屑病样模型的作用研究

目的 探讨成纤维细胞生长因子（FGF10）单克隆抗体局部外用对银屑病豚鼠模型的治疗作用。方法 应用5%盐酸普萘洛尔搽剂外涂豚鼠耳背部皮肤,诱导银屑病样动物模型。分别设置空白组、模型组、丁酸氢化可的松治疗组、FGF10抗体高（0.188 g/L）、中（0.094 g/L）、低（0.063 g/L）剂量治疗组。治疗2周后观察银屑病样模型的病理变化。采用SPSS 13.0统计软件进行统计学分析,Baker评分比较应用秩和检验,单一核细胞计数及表皮厚度比较应用方差分析（ANOVA）,多个样本均数的两两比较应用最少显著差法（LSD）。 结果 各治疗组上述各项检测指标均低于模型组（均P < 0.05）。FGF10抗体高剂量组炎细胞计数与空白组差异无统计学意义（t = 0.77,P > 0.05）,其余各治疗组炎细胞计数高于空白组及FGF10抗体高剂量组（均P < 0.05）。FGF10抗体各治疗组表皮厚度均高于丁酸氢化可的松治疗组,差异均有统计学意义（均P < 0.05）。FGF10抗体各治疗组组间表皮厚度比较,差异无统计学意义（均P > 0.05）。结论 FGF10单克隆抗体对银屑病样豚鼠模型中异常病理改变有显著调节作用,能影响角质形成细胞增殖分裂,还能显著抑制银屑病模型中炎症反应。     

Skin application of the nonsteroidal anti-inflammatory drug ketoprofen downmodulates the antigen-presenting ability of Langerhans cells in mice

Background  Ketoprofen (KP) is widely used as a topical nonsteroidal anti-inflammatory drug that inhibits prostaglandin (PG) biosynthesis. As PGE₂ upregulates the antigen-presenting activity of Langerhans cells (LCs), i.e. migration to lymph nodes and expression of immunocompetent molecules, modulation of LC functions resulting from topical application of KP is an issue to be clarified.
Objectives  To investigate the in vivo effect of KP application to the skin and the in vitro effect of KP addition to the culture on the antigen-presenting ability of murine LCs.
Methods  Ears of BALB/c mice were painted with picryl chloride (PCl) hapten, KP or both. An immunofluorescence study of epidermal sheets and a flow cytometric analysis of epidermal cell suspensions from the treated ears were performed.
Results  PCl altered the morphology of LCs and reduced their number, and simultaneous application of 10% KP maintained LC morphology and number. KP at 5% or 10% clearly decreased the PCl-augmented expression of major histocompatibility complex class II and CD86 on LCs. In cultivation of freshly isolated epidermal cells, 5 mmol L⁻¹ KP inhibited the culture-promoted expression of these molecules on LCs, whereas 100 μmol L⁻¹ indomethacin was not inhibitory. The further addition of PGE₂ to the KP-containing epidermal cell culture did not restore the expression of these molecules. Moreover, topical application of 10% KP to the sensitizing sites suppressed the development of contact hypersensitivity to PCl.
Conclusions  KP may have the potential to inhibit the antigen-presenting ability of LCs, in a PGE₂-independent manner.     

Pustular irritant dermatitis due to croton oil. Evaluation of the role played by leukocytes and complement

To elucidate the pathomechanisms of irritant pustular dermatitis and to evaluate the role of leukocytes in pustulation induced by croton oil, we compared the skin responses in leukopenic-and decomplemented guinea pigs with those in control saline-injected animals, to 1% croton oil application. Both decomplemented and control animals responded similarly to croton oil, showing erythema and pustulation at 24 h after topical application; microscopically numerous mononuclear and polymorphonuclear cells infiltrated the skin. Meanwhile, the clinical and histopathological response of leukopenic animals to croton oil was significantly depressed. Time-course study of inflammatory infiltrate in the dermis of controls revealed that mononuclear cells preceded the infiltration of polymorphonuclears. Although leukocytes constitute an important component in croton oil dermatitis, our results suggest that unclarified chemical mediators, other than complement-derived chemotactic factors, play a crucial role as a primary chemoattractant in the production of pustulation at the croton oil-applied site.     

Squamometry in seborrheic dermatitis

BACKGROUND: Seborrheic dermatitis is a corticosteroid-responsive condition. Topical corticosteroids exhibit distinct activities according to the type and cellular site of action of the hormone and its vehicle. The latter influences not only drug penetration, but also the structure and function of the horny layer. OBJECTIVE: The present study compared the early response of seborrheic dermatitis to two topical corticosteroids using objective quantifications of the stratum corneum alterations. METHOD: Squamometry was used to supplement the clinical assessment of the therapeutic activity of 0.1% hydrocortisone butyrate in an oil-in-water emulsion (Locoid Crelo) and 0.05% betamethasone 17-21 dipropionate lotion (Diprosone lotion). RESULTS: The hydrocortisone butyrate formulation had a faster onset of efficacy as documented by a greater improvement of lesions after a 1-week twice-daily treatment. Clearance or marked improvement was observed in the two treatment groups at completion of the 2-week trial. CONCLUSIONS: As the ranking of the clinical efficacy was not predicted by the intrinsic anti-inflammatory potency of the steroids, it is suggested that the vehicle contributed itself to the global in vivo efficacy. The anti-inflammatory action of hydrocortisone butyrate appears to be synergistically implemented by the emollient effect of the specially designed oil-in-water emulsion.     

Preclinical evaluation of a new topical corticosteroid methylprednisolone aceponate

Objective : Preclinical characterization of methylprednisolone aceponate. Results : The local antiinflammatory potency of methylprednisolone aceponate was equal to the very strong glucocorticoid clobetasol 17-propionate but higher than the potency of hydrocortisone 17-butyrate after topical application in 2 animal models of inflammation. Methylprednisolone aceponate is activated enzymatically in the skin. This activation proceeds faster in inflamed tissue. In contrast to clobetasol 17-propionate, methylprednisolone aceponate was devoid of systemic effects after topical application for 3 days. Finally, whereas clobetasol 17-propionate induced marked skin atrophy, methylprednisolone aceponate induced only slight atrophogenic changes after long-term application (up to 43 days) on rat skin, comparable to the effects of hydrocortisone 17-butyrate. Conclusions : Methylprednisolone aceponate combines high local antiinflammatory potency with very low systemic side effects and only minor local atrophogenic activity. The reason for the dissociation between local antiinflammatory and atrophogenic effects is not known so far. It may be speculated that one of the reasons for the very strong local antiinflammatory activity may reside in the faster enzymatic activation in inflamed tissue. Methylprednisolone aceponate represents a new corticosteroid with which it is possible to improve the dissociation between desired antiinflammatory activity and undesired side effects of topical glucocorticoids.     

Protective effects of a cream containing Dead Sea minerals against UVB-induced stress in human skin

Background:  Dead Sea (DS) mud and water are known for their unique composition of minerals, and for their therapeutic properties on psoriasis and other inflammatory skin diseases. Their mode of action, however, remains poorly known.
Objectives:  To analyse the ability of Dermud™, a leave-on skin preparation containing DS mud and other ingredients like DS water, zinc oxide, aloe-vera extract, pro-vitamin B5 and vitamin E, to antagonize biological effects induced by UVB irradiation in skin when topically applied in organ cultures.
Methods:  We have used human skin organ cultures as a model to assess the biological effects of UVB irradiation and of Dermud™ cream topical application. Skin pieces were analysed for mitochondrial activity by MTT assay, for apoptosis by caspase 3 assay, for cytokine secretion by solid phase ELISA, for overall antioxidant capacity by ferric reducing antioxidant power and Oxygen radical absorbance capacity assays (epidermis) or by cyclic voltammetry (external medium), and for uric acid (UA) content by HPLC.
Results:  We report that UVB irradiation decreases cell viability, total antioxidant capacity and UA contents in the epidermis of skin organ cultures, while increasing the levels of apoptosis in cells and their cytokine secretion. Topical application of Dermud™ decreased all these effects significantly.
Conclusions:  Our results clearly show that Dermud™ has protective, anti-oxidant and anti-inflammatory properties that can antagonize biological effects of UVB irradiation in skin. It may therefore be able to reduce skin photodamage and photoaging, and more generally to reduce oxidative stress and inflammation in skin pathologies.     

Liver X receptor activators display anti-inflammatory activity in irritant and allergic contact dermatitis models: liver-X-receptor-specific inhibition of inflammation and primary cytokine production

Activators of liver X receptors (LXR) stimulate epidermal differentiation and development, but inhibit keratinocyte proliferation. In this study, the anti-inflammatory effects of two oxysterols, 22(R)-hydroxy-cholesterol (22ROH) and 25-hydroxycholesterol (25OH), and a nonsterol activator of LXR, GW3965, were examined utilizing models of irritant and allergic contact dermatitis. Irritant dermatitis was induced by applying phorbol 12-myristate-13-acetate (TPA) to the surface of the ears of CD1 mice, followed by treatment with 22ROH, 25OH, GW3965, or vehicle alone. Whereas TPA treatment alone induced an approximately 2-fold increase in ear weight and thickness, 22ROH, 25OH, or GW3965 markedly suppressed the increase (greater than 50% decrease), and to an extent comparable to that observed with 0.05% clobetasol treatment. Histology also revealed a marked decrease in TPA-induced cutaneous inflammation in oxysterol-treated animals. As topical treatment with cholesterol did not reduce the TPA-induced inflammation, and the nonsterol LXR activator (GW3965) inhibited inflammation, the anti-inflammatory effects of oxysterols cannot be ascribed to a nonspecific sterol effect. In addition, 22ROH did not reduce inflammation in LXRbeta-/- or LXRalphabeta-/- animals, indicating that LXRbeta is required for this anti-inflammatory effect. 22ROH also caused a partial reduction in ear thickness in LXRalpha-/- animals, however (approximately 50% of that observed in wild-type mice), suggesting that this receptor also mediates the anti-inflammatory effects of oxysterols. Both ear thickness and weight increased (approximately 1.5-fold) in the oxazolone-induced allergic dermatitis model, and 22ROH and GW3965 reduced inflammation by approximately 50% and approximately 30%, respectively. Finally, immunohistochemistry demonstrated an inhibition in the production of the pro-inflammatory cytokines interleukin-1alpha and tumor necrosis factor alpha in the oxysterol-treated sites from both TPA- and oxazolone-treated animals. These studies demonstrate that activators of LXR display potent anti-inflammatory activity in both irritant and allergic contact models of dermatitis, requiring the participation of both LXRalpha and LXRbeta. LXR activators could provide a new class of therapeutic agents for the treatment of cutaneous inflammatory disorders.     

A time course investigation of the fluorescence induced by topical application of 5-aminolevulinic acid and methyl aminolevulinate on normal human skin

Background: Treatment of non-melanoma skin cancers (NMSC) with topical photodynamic therapy (PDT) is a treatment of choice for many clinicians. The two most commonly used PDT photosensitizer precursors are 5-aminolevulinic acid (ALA) and methyl aminolevulinate (MAL). Current PDT treatment regimes advise longer (4–6 h) application times for ALA and shorter times (3 h) for MAL.
Aims: To establish the time course characteristics of protoporphyrin IX (PpIX) fluorescence following the application of ALA and MAL in normal skin.
Methods: A total of 17 healthy volunteers were recruited, and both ALA and MAL were applied to the inner forearm for varying times (1–6 h). PpIX fluorescence was detected using a non-invasive spectroscopy system.
Results and conclusion: PpIX fluorescence (following the application of either ALA or MAL) is dependent on duration of application. Following the application of ALA for 1–3 h peak fluorescence was noted at 7 h. Longer duration times (4–6 h) resulted in sustained fluorescence, which peaked at 24 h. MAL-induced fluorescence peaked at 7 h and was significantly decreased by 24 h for all application times. ALA induced fluorescence was shown to be significantly greater than MAL. The findings from this study have shown that potentially it would be more beneficial to apply ALA for shorter periods of time and MAL for longer than current practice.